Fernando David Perez, 58

Fernando David Perez, a 58-year-old Latino, died on Thursday, Nov. 8, after he was stabbed in the 500 block of West 9th Street, between Hope Street and Grand Avenue, in downtown Los Angeles, according to Los Angeles County coroner's records.

Perez, a homeless man who stayed in the downtown area where the stabbing occurred, was sitting on a bench at 8:30 p.m. when he was attacked by a tall, thin white man in a grey hooded sweatshirt that read "Thrasher" across the front, said Los Angeles police Det. Jason Sharman during a Dec. 19 news conference.

The assailant stabbed Perez multiple times with what appeared to be a screwdriver or ice pick, and then picked up a backpack next to the victim and walked away, Sharman said after the news conference.

Perez was taken to a nearby hospital, where he was pronounced dead two days later at 5:18 a.m., according to coroner's records. The cause of death was listed as a stab wound to the back.

Investigators found video footage of the attack on nearby surveillance cameras, and are offering a $50,000 reward for information leading to the arrest and conviction of the attacker, Capt. Marc Reina said during the news conference.

In the video, Perez appears to be sitting on the end of a bench just inside Grand Hope Park when the attacker approached and stabbed him in the back. When Perez fell, dropping a backpack onto the ground, the man stabbed him at least two more times before scooping up the dark-colored backpack, gesturing threateningly and then walking away.

Investigators don't know if the backpack belonged to Perez or the suspect, Sharman said. They found surveillance video of Perez picking up a dark backpack about 10 minutes before the stabbing, about a block away from where he was attacked, Sharman said, but it's not clear if the backpack belonged to Perez, or if he found it and just picked it up.

The motive could be a robbery, Sharman said, or it could be that Perez had picked up the man's backpack, and was attacked when the man went to get it back.

The police video also includes footage of the attacker and a dark-haired young white woman standing in front of a vending machine and then taking the down escalators in the 505 Flower building, about five blocks from the stabbing site. In that video, the man has a dark-colored backpack on his shoulder.

The man drew attention earlier in the evening when he was seen walking up and down in front of a Ralphs grocery store parking lot, Sharman said. "He appeared agitated."

Investigators believe the man and the young woman were in the area for some time prior to the stabbing, but they don't believe the two are homeless, Sharman said.

Some people reported seeing a lime green Chevy Spark with Florida license plates near the crime scene, and it's possible the couple may have gotten into that car and drove away, Sharman said. "We don't know if they are tourists or locals."

During the attack, the man was also wearing grey jogging pants and black shoes with white soles, according to investigators. Earlier in the afternoon, he was seen wearing a white T-shirt with an unknown logo on the front and a purple or light blue hat with a white logo. His female companion was wearing a black long-sleeve shirt, black pants with white stripes, a dark-colored hat and white shoes, and carrying a black backpack.

Anyone with information is asked to call the Central Homicide detectives at (213) 996-1878. Those wishing to remain anonymous should call Crime Stoppers at (800) 222-8477.